With business travellers back on the flying trail, the big pre-Christmas issue - the switchover from Aer Lingus's Gold Circle loyalty scheme to the new AerClub - hasn't gone away.

This column, which featured the story last month, has since been contacted by a number of frequent flyers, and the social media storm on twitter is still in full flow.

Many frequent flyers who've been transferred to the new scheme run in association with Avios are angry that they've been placed on its lowest rung - Green Tier - which doesn't have essentials like fast-track security and airport lounge access. One academic wrote to me to vent his frustration, claiming: "In November 2015 when they announced that they were transitioning to a new club I contacted them to ask what would happen to my [Gold Circle] points (I am an 'applicant member').

"After some initial confusion they told me that all points earned previously would count towards the new club. They told me this on the phone, in a personal email, and again in a generic email sent to all Gold Circle members in the summer of 2016. In other words, they promised that your place in the queue to reach Gold Circle status would remain the same as it was once the new club was introduced."

He said that he "was put back to the start of the queue" with the new scheme, adding: "I saw in your report that many people said that they would prefer to support an Irish airline. I guess that is part of being Irish, but it is also part of our identity to stand up to the big guy when they treat us like worthless ****. For me, if there were direct flights on any of the routes I want to fly with any airline other than Aer Lingus and Ryanair (who despite improvements are still terrible - ie, not enough recline space to use a laptop on a Ryanair flight) I would."

Another reader received his Gold Circle card in the post - a month before it was effectively worthless, and noted widespread confusion among loyal passengers.

"Everybody seems to be misinformed, conversion hasn't gone well and nobody got level they were expecting," he said.

"Those who were on applicant level and not Gold Circle haven't been awarded tier credits or if they have, the conversion again is very poor."

Flyers were even more vocal on twitter. Here's a snapshot: "Years of loyalty with @AerLingus all in vain. This new @AerClub really doesn't reward loyalty at all. I'm disgusted."

Another said: "Flights booked with Ryanair to London have given up with @AerLingus not co-operating with passengers using the #aerclub programme." Another: "Judging by the other people commenting to @aerclub - I'm not the only person finding @AerLingus is making a hames of this launch."

Or: "@AerLingus still haven't sorted my @AerClub membership, & @Ryanair flights are half the price + better times. Guess that's my decision made." Or: "Amazed at the shambles that @AerLingus have made in their attempts to roll out aer club."

Another tweeted that it "takes over a month to have AerClub act updated with flights taken, any other airline takes 24 hours." Aer Lingus, in fairness, quickly responded. "This is just during the migration process," it said.

Aer Lingus responded to this column's queries - one of which was whether Silver Tier members (second lowest) could access lounges.

"Silver Tier status members can access Aer Lingus lounges in airports where we operate a direct service in Ireland or the USA and in London Heathrow," it said.

On points conversion, it said: "Previous Gold Circle members who had tiered status, eg Gold, Prestige or Elite, received two Avios Points for every Gold Circle point. In addition, they received an Avios welcome bonus of 250 Avios points. For Gold Circle members who were Applicant members (eg, not tiered members) and were moving across to Green membership in AerClub, they received an Avios welcome bonus of 250 Avios points." It said those who had flights in the 12 months before migration were awarded Tier Credits based on the level of their flight activity (eg Gold Circle points accrued).

It argued its "loyalty programme has hundreds and thousands of members. For a vast majority the transition from Gold Circle to AerClub has been relatively smooth", but did "appreciate some members have experienced some difficulties migrating to the new AerClub programme. The Aer Lingus call centre teams have been trained to handle customer queries, some of which can be resolved quickly, while others require further investigation."

It said "the purpose of the new AerClub programme is to build a world class rewards system for our loyal customers", and said customers could collect points through retailers and online, and not just through flying mileage.

"We greatly appreciate the loyalty of our customers... the programme is still in transition phase and we believe once it is up and running, our loyal customers will reap great benefits."

n But there is some good news for the national airline - in the shape of this week's airline punctuality league by aviation analysts OAG. It ranked eighth among European airlines for the timeliness of its departures and arrivals (KLM came first).

In the airports category, Birmingham topped the medium-sized category, while Munich came in ninth in the largest-sized category. One word of warning: not all carriers take part, but it's still a handy guide.

n Business class is one thing: flying in a private jet is quite another. Today sees a new leap in luxury, with the first take-off from London to New York of a new, dedicated transatlantic service by private jet.

If you haven't got the cash to buy or lease your own Gulfstream, you can now rideshare between the two cities using a new US start-up, Bliss Jet. It's promising luxury travel without the stress of a large airport by flying between London Stansted and La Guardia.

You'll be sharing your latest-generation Gulfstreams with around nine others, but it comes with a hefty price tag - $11,995 (around €11,300) each way.

But if your time is worth that, check-in is only 30 minutes before departure, and Bliss Jet says even the security staff are a cut above the rest, "comprised of retired FBI and United States Secret Service agents; federal air marshals; current and retired members of local law enforcement and the US armed services".

Dedicated business-only routes are a gamble though: I travelled to New York with Silverjet back in 2008 (a decent-priced £900 each way) - but weeks later it was out of business.

Its London airport, far-off Luton, was seen as off-putting to Heathrow veterans, so it'll be interesting to see how Bliss Jet fares with Stansted, despite its direct rail link to London. Still, there seems to be a market for the high life: the first six flights are booked out, so it'll be January 29 before you can part with your cash.